Inspection Procedure 28

CIRCUIT OPERATION
- The PCM sends a duty signal to the fan controller according to engine coolant temperature, vehicle speed, and the condition of the A/C switch. The closer the average voltage at the terminal becomes to five volts, the higher the fan speed becomes).

TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Malfunction of the fan motor relay.
- Malfunction of the fan motor.
- Malfunction of the fan controller.
- Improper connector contact, open or short-circuited harness wire.
- PCM failed.




WIRING DIAGRAM




CONNECTORS

DIAGNOSIS




STEP 1. Measure the voltage at the PCM connector C-39.
1. Disconnect the connector C-39 and measure the harness side.
2. Turn the ignition switch "ON."
3. Measure the voltage between the terminal 18 and ground.
- Voltage should be between 4.8 and 5.2 volts. (Fan rotates at high speed.)
4. Connect a jumper cable between 18 and ground.
- Fan stops.
5. Turn the ignition switch "OFF."
If within specifications, go to Step 2.
If not within specifications, go to Step 3.




STEP 2. Check the harness connector C-39 at the PCM for damage.
If harness connector C-39 is not damaged, replace the PCM.
If the harness connector C-39 is damaged, repair or replace them. Refer to Harness Connector Inspection >. Then check the malfunction is eliminated.




STEP 3. Check the harness wire between the fan controller connector A-30 and the PCM connector C-39.

NOTE: Check the wire after checking the intermediate connector C-04. If the intermediate connector C-04 is damaged, repair or replace it. Refer to Harness Connector Inspection >. Then check that the malfunction is eliminated.

If the wire between the fan controller connector A-30 and PCM connector C-39 is damaged, repair it.
If the wire between the fan controller connector A-30 and PCM connector C-39 is not damaged, check the radiator fan and A/C compressor fan circuit. Refer to Diagnosis.
Then check the malfunction is eliminated.